Acknowledged
Created: Sep 23, 2025
Updated: Oct 7, 2025
Found In Version: 10.22.33.1
Severity: Standard
Applicable for: Wind River Linux LTS 22
Component/s: Kernel
In the Linux kernel, the following vulnerability has been resolved:[EOL][EOL]ocfs2: fix recursive semaphore deadlock in fiemap call[EOL][EOL]syzbot detected a OCFS2 hang due to a recursive semaphore on a[EOL]FS_IOC_FIEMAP of the extent list on a specially crafted mmap file.[EOL][EOL]context_switch kernel/sched/core.c:5357 [inline][EOL] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961[EOL] __schedule_loop kernel/sched/core.c:7043 [inline][EOL] schedule+0x165/0x360 kernel/sched/core.c:7058[EOL] schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115[EOL] rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185[EOL] __down_write_common kernel/locking/rwsem.c:1317 [inline][EOL] __down_write kernel/locking/rwsem.c:1326 [inline][EOL] down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591[EOL] ocfs2_page_mkwrite+0x2ff/0xc40 fs/ocfs2/mmap.c:142[EOL] do_page_mkwrite+0x14d/0x310 mm/memory.c:3361[EOL] wp_page_shared mm/memory.c:3762 [inline][EOL] do_wp_page+0x268d/0x5800 mm/memory.c:3981[EOL] handle_pte_fault mm/memory.c:6068 [inline][EOL] __handle_mm_fault+0x1033/0x5440 mm/memory.c:6195[EOL] handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364[EOL] do_user_addr_fault+0x764/0x1390 arch/x86/mm/fault.c:1387[EOL] handle_page_fault arch/x86/mm/fault.c:1476 [inline][EOL] exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532[EOL] asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623[EOL]RIP: 0010:copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline][EOL]RIP: 0010:raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline][EOL]RIP: 0010:_inline_copy_to_user include/linux/uaccess.h:197 [inline][EOL]RIP: 0010:_copy_to_user+0x85/0xb0 lib/usercopy.c:26[EOL]Code: e8 00 bc f7 fc 4d 39 fc 72 3d 4d 39 ec 77 38 e8 91 b9 f7 fc 4c 89[EOL]f7 89 de e8 47 25 5b fd 0f 01 cb 4c 89 ff 48 89 d9 4c 89 f6 <f3> a4 0f[EOL]1f 00 48 89 cb 0f 01 ca 48 89 d8 5b 41 5c 41 5d 41 5e 41[EOL]RSP: 0018:ffffc9000403f950 EFLAGS: 00050256[EOL]RAX: ffffffff84c7f101 RBX: 0000000000000038 RCX: 0000000000000038[EOL]RDX: 0000000000000000 RSI: ffffc9000403f9e0 RDI: 0000200000000060[EOL]RBP: ffffc9000403fa90 R08: ffffc9000403fa17 R09: 1ffff92000807f42[EOL]R10: dffffc0000000000 R11: fffff52000807f43 R12: 0000200000000098[EOL]R13: 00007ffffffff000 R14: ffffc9000403f9e0 R15: 0000200000000060[EOL] copy_to_user include/linux/uaccess.h:225 [inline][EOL] fiemap_fill_next_extent+0x1c0/0x390 fs/ioctl.c:145[EOL] ocfs2_fiemap+0x888/0xc90 fs/ocfs2/extent_map.c:806[EOL] ioctl_fiemap fs/ioctl.c:220 [inline][EOL] do_vfs_ioctl+0x1173/0x1430 fs/ioctl.c:532[EOL] __do_sys_ioctl fs/ioctl.c:596 [inline][EOL] __se_sys_ioctl+0x82/0x170 fs/ioctl.c:584[EOL] do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline][EOL] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94[EOL] entry_SYSCALL_64_after_hwframe+0x77/0x7f[EOL]RIP: 0033:0x7f5f13850fd9[EOL]RSP: 002b:00007ffe3b3518b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010[EOL]RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f5f13850fd9[EOL]RDX: 0000200000000040 RSI: 00000000c020660b RDI: 0000000000000004[EOL]RBP: 6165627472616568 R08: 0000000000000000 R09: 0000000000000000[EOL]R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe3b3518f0[EOL]R13: 00007ffe3b351b18 R14: 431bde82d7b634db R15: 00007f5f1389a03b[EOL][EOL]ocfs2_fiemap() takes a read lock of the ip_alloc_sem semaphore (since[EOL]v2.6.22-527-g7307de80510a) and calls fiemap_fill_next_extent() to read the[EOL]extent list of this running mmap executable. The user supplied buffer to[EOL]hold the fiemap information page faults calling ocfs2_page_mkwrite() which[EOL]will take a write lock (since v2.6.27-38-g00dc417fa3e7) of the same[EOL]semaphore. This recursive semaphore will hold filesystem locks and causes[EOL]a hang of the fileystem.[EOL][EOL]The ip_alloc_sem protects the inode extent list and size. Release the[EOL]read semphore before calling fiemap_fill_next_extent() in ocfs2_fiemap()[EOL]and ocfs2_fiemap_inline(). This does an unnecessary semaphore lock/unlock[EOL]on the last extent but simplifies the error path.